I recently installed two electric meters with current transformers, one on a farm house and one on a dairy to settle a dispute among a family run business regarding electric bills. The idea being that there are three areas needing metering and these two subtracted from the overall usage would give the third. The reason for not metering the third is that it is spread over several circuits.

My question relates to the KWH and KVAr readings. The dairy shows significantly higher KVAr than KWH and the farm house higher on the KWH, presumably due to the different loads types being utilised. The meter supplier suggested adding the the two readings together to obtain the actual usage for each metered area. However this does not relate to the overall bill and effectively means that they are using more than the overall electric bill.
How can I derive the actual usage from the readings? it appears that taking the higher reading for KWH or KVAr for each supply is nearer the mark, when compared to the overall electric bill.
thanks in advance.